The period in Argentina when it was ruled by a military junta (1976-1982) is called the "Dirty War."

One of Sosa's firmest beliefs was:

Dictators come, dictators go. Because everything changes.

Mercedes Sosa, known as La Negra, (July 9, 1935 – October 4, 2009) was an Argentine singer who was and remains immensely popular throughout Latin America and internationally. With her roots in Argentine folk music, Sosa became one of the preeminent exponents of nueva canción. She gave voice to songs written by both Brazilians and Cubans. She was best known as the "voice of the voiceless ones."

After the military junta of Jorge Videla came to power in 1976, the atmosphere in Argentina grew increasingly oppressive. At a concert in La Plata, Argentina, in 1979, the late Mercedes Sosa was searched and arrested on stage, along with the attending crowd. Their release came about through international intervention. Banned in her own country, she moved to Paris and then to Madrid.

Comments:

According to a posted comment from Martin Lutteral on YouTube | posted 3 years ago —
(as I write this in 2016)

Balderrama is the surname * of Don Juan Balderrama. He had an eatery in Salta, Argentina, which the song refers to – "Pena Boliche Balderrama." In his tavern, locals would gather to sing folk songs and to eat and drink in parties that would last until dawn. He passed away in his beloved Salta on April 2, 2013, at age 79.

Señor Balderrama had the "peña" that we hear in this song. ["Feelings of sadness and tenderness produced by the suffering of someone."]

* Nathaniel Segal - My grasp of Spanish is from three semesters in college – 2009-2010. I've never experienced language immersion, so I speak very little. My translation is an academic exercise. My familiarity with Argentina comes from a month's visit in 2000, but I didn't travel outside Buenos Aires. As little as I understand the culture of that district, I'm at a complete loss to appreciate the northern region of the country close to Bolivia (about 800 miles, 1290 km, from Buenos Aires as the crow flies) where the city of Salta lies.

Please compare my poetic translation with the translation from the YouTube video above. I've visualized the background of the song's origin. Does Balderrama's lullaby sing or does he himself sing? I'm troubled by the appearance of the driver – cochero. Is this their veiled reference to the secret police of that time? Is this an element of the "peña" that Martin Lutteral refers to? Regardless, it is a beautiful song, and the lyrics are beautiful poetry.

* Che - I've seen both parts of this movie, more than one time, awhile back. I'm not prepared to review the film now. I'd like to correlate the song "Balderrama" with the film's content. Part 2 of the film is tedious and otherwise disappointing.